We’ve to create a JavaScript array filled with all zeroes in our code.
In this article, we’ll look at how to create a zero-filed JavaScript array.
Array.prototype.fill
We can use the fill array method to fill all the entries of an array with the values we want.
For instance, we can write:
const arr = new Array(10).fill(0);
console.log(arr);
The Array constructor takes the length of an array if we only pass one argument into it.
fill takes the value we want to fill the array with.
Then arr is [0, 0, 0, 0, 0, 0, 0, 0, 0, 0] .
fill is available since ES6.
The apply and map Methods
We can also use the Array.apply method to create an empty array that we can use the map method with.
Then we pass in a callback that returns the value we want into the map method.
For instance, we can write:
const arr = Array.apply(undefined, Array(10)).map(() => 0);
console.log(arr);
We call apply with Array(10) to create an array with 10 slots that we can fill with map .
Then in map , we just pass in a callback that returns 0 to fill all the entries with zeroes.
So we get the same result as the previous example.
Array.from
The Array.from method is an array static method that lets us return an array derived from another array.
So we can use it to map the values from one array to another, including an empty array.
For instance, we can write:
const arr = Array.from(Array(10), () => 0)
console.log(arr);
We call Array.from with Array(10) to let us map the empty array with 10 slots to an array with stuff inside.
The 2nd argument is a callback that returns 0 so we fill all the entries with zeroes.
Therefore, we get the same result as before.
Another way to use Array.from is to pass in an object with the length property set to the array length we want.
To do this, we write:
const arr = Array.from({
length: 10
}, () => 0)
console.log(arr);
And we get the same result as before.
Conclusion
We can create a zero-filled array with JavaScript by using the fill method or the Array.from method.
Also, we can use the Array constructor to create an array.
